From b1f211509a8397d90df4d9a2867172dbd096536f Mon Sep 17 00:00:00 2001
From: robokaso <robokaso@2e8e966d-6415-0410-94b9-dc4e65435d03>
Date: Mon, 22 Sep 2008 09:05:17 +0000
Subject: [PATCH] RESOLVED - BATCH-843: FlatFileItemWriter handling of failure
 in LineAggregator

---
 .../batch/item/file/FlatFileItemWriter.java   | 19 ++++---
 .../item/file/FlatFileItemWriterTests.java    | 54 +++++++++++++++----
 2 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemWriter.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemWriter.java
index 3636a1b9f..4d5b6b7b7 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemWriter.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemWriter.java
@@ -186,15 +186,19 @@ public class FlatFileItemWriter<T> extends ExecutionContextUserSupport implement
 
 		OutputState state = getOutputState();
 
+		StringBuilder lines = new StringBuilder();
+		int lineCount = 0;
 		for (T item : items) {
-			String line = lineAggregator.aggregate(item) + lineSeparator;
-			try {
-				state.write(line);
-			}
-			catch (IOException e) {
-				throw new FlushFailedException("Could not write data.  The file may be corrupt.", e);
-			}
+			lines.append(lineAggregator.aggregate(item) + lineSeparator);
+			lineCount++;
 		}
+		try {
+			state.write(lines.toString());
+		}
+		catch (IOException e) {
+			throw new FlushFailedException("Could not write data.  The file may be corrupt.", e);
+		}
+		state.linesWritten += lineCount;
 	}
 
 	/**
@@ -394,7 +398,6 @@ public class FlatFileItemWriter<T> extends ExecutionContextUserSupport implement
 
 			outputBufferedWriter.write(line);
 			outputBufferedWriter.flush();
-			linesWritten++;
 		}
 
 		/**
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemWriterTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemWriterTests.java
index 9f2c47fcb..db608ead2 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemWriterTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemWriterTests.java
@@ -16,10 +16,7 @@
 
 package org.springframework.batch.item.file;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.*;
 
 import java.io.BufferedReader;
 import java.io.File;
@@ -27,8 +24,10 @@ import java.io.FileReader;
 import java.io.IOException;
 import java.io.Writer;
 import java.nio.charset.UnsupportedCharsetException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.List;
 
 import org.junit.After;
 import org.junit.Before;
@@ -209,7 +208,7 @@ public class FlatFileItemWriterTests {
 			public void write(Writer writer) throws IOException {
 				writer.write("footer");
 			}
-			
+
 		});
 
 		writer.open(executionContext);
@@ -235,7 +234,7 @@ public class FlatFileItemWriterTests {
 		for (int i = 1; i <= 8; i++) {
 			assertEquals("testLine" + i, readLine());
 		}
-		
+
 		assertEquals("footer", readLine());
 
 		// 3 lines were written to the file after restart
@@ -321,7 +320,7 @@ public class FlatFileItemWriterTests {
 			public void write(Writer writer) throws IOException {
 				writer.write("a\nb");
 			}
-			
+
 		});
 		writer.open(executionContext);
 		writer.write(Collections.singletonList(TEST_STRING));
@@ -338,7 +337,7 @@ public class FlatFileItemWriterTests {
 			public void write(Writer writer) throws IOException {
 				writer.write("a\nb");
 			}
-			
+
 		});
 		writer.open(executionContext);
 		writer.write(Collections.singletonList(TEST_STRING));
@@ -358,7 +357,7 @@ public class FlatFileItemWriterTests {
 			public void write(Writer writer) throws IOException {
 				writer.write("a\nb");
 			}
-			
+
 		});
 		writer.open(executionContext);
 		writer.write(Collections.singletonList(TEST_STRING));
@@ -383,7 +382,7 @@ public class FlatFileItemWriterTests {
 			public void write(Writer writer) throws IOException {
 				writer.write("a\nb");
 			}
-			
+
 		});
 		writer.open(executionContext);
 		writer.write(Collections.singletonList(TEST_STRING));
@@ -410,4 +409,39 @@ public class FlatFileItemWriterTests {
 		assertEquals(TEST_STRING, lineFromFile);
 	}
 
+	@Test
+	/**
+	 * Nothing gets written to file if line aggregation fails.
+	 */
+	public void testLineAggregatorFailure() throws Exception {
+
+		writer.setLineAggregator(new LineAggregator<String>() {
+
+			public String aggregate(String item) {
+				if (item.equals("2")) {
+					throw new RuntimeException("aggregation failed on " + item);
+				}
+				return item;
+			}
+		});
+		List<String> items = new ArrayList<String>() {
+			{
+				add("1");
+				add("2");
+				add("3");
+			}
+		};
+
+		writer.open(executionContext);
+		try {
+			writer.write(items);
+			fail();
+		}
+		catch (RuntimeException expected) {
+			assertEquals("aggregation failed on 2", expected.getMessage());
+		}
+		
+		// nothing was written to output
+		assertNull(readLine());
+	}
 }